(3:45 p.m. EST; updated 11:30 a.m. EST) -- Royal Caribbean's only ship currently in service, Quantum of the Seas, has returned to Singapore after a potential COVID-19 case, with most passengers being allowd to disembark. The Singapore Ministry of Health said that the passenger who initially tested positive onboard, an 83-year-old man from Singapore, had reported to the ship's medical center with diarrhea. As part of the protocols, he was given a PCR test onboard, which came back positive. He was immediately put into isolation and contact tracing went into effect. Since the ship returned to Singapore, the original sample has been re-tested at the country's National Public Health Laboratory (NPHL), and has come back negative for COVID-19, the Minstry said. A second fresh sample tested by NPHL has also come back negative. NPHL will conduct another test tomorrow to confirm his COVID-19 status.Meanwhile, close contacts of the case have been placed in quarantine, while the remaining passengers and crew are gradually being allowed off while contact tracing continues to be carried out. Angie Stephen, Managing Director of Royal Caribbean, Asia Pacific confirmed that those passengers not traced to the affected guest will have a normal rapid antigen test at the end of the cruise, adding that the "goal is to take care of the COVID guest first."Those passengers can then go home and go about their daily activities including going to work, but have been advised to monitor their health for the next 14 days."One guest aboard Quantum of the Seas tested positive for coronavirus after checking in with our medical team," the line said in a statement. "We identified and isolated all guests and crew who had close contact with this guest, and each of those individuals have subsequently tested negative for the virus."The ship is returning to port today local time in accordance with government protocols and will debark guests after a review of contact tracing is completed."We are in communication with the Singapore government and appreciate their guidance as we work together to protect the health and safety of our guests and crew."We worked closely with the government to develop a thorough system that tests and monitors all guests and crew and follows public health best practices. That we were able to quickly identify this single case and take immediate action is a sign that the system is working as it was designed to do."An announcement was made by the ship's captain around 1:50 a.m. Singapore time, according to Heidi Sarna, co-founder of the website
QuirkyCruise, who is onboard the Royal Caribbean ship on assignment for Cruise Critic and has since disembarked."The captain just made an announcement 1 minute ago that we're heading back to port by 8 a.m.," Sarna told Cruise Critic.The cruise, which left Singapore on December 7, had just finished its second day at sea. (Given the time zone differences, the announcement came early in the morning Wednesday, December 9, local time).Quantum of the Seas' return to service had been a milestone for Royal Caribbean, as it was the first ship for the line to resume sailing since the COVID-19 virus shut down cruising worldwide in March 2020. The ship made its first in a series of two-, three- and four- day cruises to nowhere on December 1.Working with the Singapore government, the line had instituted a wide range of new health and safety protocols. Chief among them: new ventilation system upgrades, required PCR testing both before boarding and disembarkation; mask wearing; social distancing and more. (Read a Cruise Critic member's live report from that first sailing, which was completed without incident).All passengers were required to be Singapore residents. (Sarna lives in Singapore) All onboard have been sporting two contact-tracing devices: one being Royal Caribbean's new Tracelet wearable wristband and the other being the "trace together" phone app required by the Singapore government.Passengers were required to "tap" their cabin keycard as they moved around the ship as another means of tracing, Sarna said. In addition, temperatures were taken at certain venues around the ship, such as the SeaPlex water sports and entertainment areas, to enter.Singapore has a very low rate of COVID-19 cases. The daily government briefing on the virus for December 8 noted that there were zero new locally transmitted cases in the community, and only 12 imported cases from people coming into the country, with all of those put in quarantine. All in all, the island nation has 80 active cases.Capacity for Quantum of the Seas has been limited, and there are 1,680 passengers currently onboard, Sarna said. That includes 474 children under 18, as local schools are on break. At double occupancy before the pandemic, the ship held 4,905 passengers.The 1,147 crew for the ship do come from countries beyond Singapore, but they are required to go through a two-week quarantine before they board the ship, the hotel director told Sarna.Until the captain's announcement, the cruise felt safe and normal, even with the new protocols, Sarna said."I have felt very safe during the cruise so far, the crew has been very fastidious with having us tap our cabin key cards at many points all over the ship, to the point of tedium," she told Cruise Critic. "Crew was cleaning the ship constantly, and everyone was wearing masks."On Wednesday morning, passengers received two letters -- one from Royal Caribbean and another from the Singapore Ministry of Health -- to their cabins providing more details on the situation onboard and plans, Sarna said. The letter from Royal Caribbean stated only one passenger onboard has tested positive and that as a precaution, all passengers would be required to stay isolated in their cabins for the duration of the trip. The letter from the Ministry of Health said that the agency would reach out to passengers who were in contact with the ill guest, and others will be required to monitor their health for the next 14 days and undergo a swab test at the end of that period. PCR tests required of passengers were required to be taken within 48 to 72 hours before boarding -- and not dockside, Sarna noted. Genting, which is also running cruises from Singapore, do rapid antigen COVID-19 tests at the terminal before people get onboard. While rapid response COVID-19 tests have led to successful European sailings this summer and fall on MSC Cruises and Costa Cruises, the double PCR testing did not catch the virus on a November sailing on SeaDream Yacht Club, which led to an outbreak.Cruise Critic will update this story as more information becomes available.